Field of the Invention
The present invention relates to a method for forming a patterned film using a lift-off method. The present invention also relates to a method for producing a liquid ejection head such as an ink jet recording head.
Description of the Related Art
By forming a penetration port in a silicon substrate, various micro electro mechanical system (MEMS) devices are produced. An example thereof is a liquid ejection head that ejects a liquid. The liquid ejection head is exemplified by an ink jet recording head.
In the ink jet recording head, an energy generating element for applying energy to eject an ink is formed on a top surface of a silicon substrate. On the top surface of the substrate, an ejection port forming member is also formed, and an opening (ejection port) that ejects an ink is formed above the energy generating element. In the silicon substrate, a penetration port is formed, and through the penetration port, an ink is supplied from the back surface of the substrate to the top surface.
In recent years, the ink jet recording head is required to have higher long-term reliability, and a liquid resistant film is formed on an ink liquid contact part in some cases. The technique of patterning the liquid resistant film is exemplified by a technique called lift-off method that is a microfabrication technique for semiconductors. The lift-off method is a method for removing a mask material including a photoresist as a coating on a silicon substrate and a film formed on the mask material from the silicon substrate when a pattern or the like is formed on a plate-shaped workpiece such as a silicon substrate. A patterning method using the lift-off method is disclosed in Japanese Patent Application Laid-Open No. 2008-187164.